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Tuning FAQ

Q. What is the major benefit of using SuperTrapp products?
Tunability, quality, and years of performance exhaust experience and testing. We do not release SuperTrapp products to the market unless we can show a documented performance improvement. SuperTrapp tunable disc mufflers have been proven to make power for years. The reason is that SuperTrapp discs provide a scavenging effect. Here’s how it works: the gap between each disc ranges from .023-in. wide on the inside of the muffler, to .028-in. on the external open edge. As hot exhaust gases pass through the discs to exit the muffler, they enter a larger area, creating a slight pressure drop as the gas expands, creating a scavenging effect for the hot gas still inside the muffler. Adding discs increases the size of the exhaust outlet area. Removing discs decreases the exhaust outlet surface area. Many competitors have tried to copy our disc design, but have never been able to duplicate the performance of genuine SuperTrapp discs.

Q. How do the diffuser discs work?
SuperTrapp is the original tunable muffler. The SuperTrapp exhaust system allows you to adjust, or “fine tune,” the sound level, powerband and performance. SuperTrapp’s exhaust outlet is formed by a precise gap between a series of individual discs. Adding discs increases the size of the exhaust outlet, increases exhaust flow and exhaust tone while reducing backpressure. More discs move the power band up to give you more top-end power, and lean out the carbureted fuel mixture. Removing discs decreases the size of the exhaust outlet, decreases exhaust tone, and exhaust flow while backpressure is increased. Fewer discs tend to increase low-end torque and richen the carbureted fuel mixture. Diffuser discs allow you to compensate for changes in altitude and air temperature without re-jetting or changing your air intake. And, besides reducing noise, our discs function as United States Forest Service-approved spark arrestors (USFS T-102), making them a safer choice for off-road motorcycles and ATVs.

Q. How do SuperTrapp mufflers reduce noise?
Sound energy in SuperTrapp mufflers is reduced in two ways: it is absorbed through a perforated core inside the body of the muffler, and it is diffused 360º radially as the exhaust passes through the discs. The number of discs used determines how much total sound energy will be absorbed and diffused. Fewer discs will have less open area and tone down the exhaust note. Most mufflers today reduce noise levels in several different ways, such as sound absorption, reflection using baffles or resonating chambers, or restriction. Physics tells us that air in motion does not like to change direction. Original equipment mufflers typically change the direction of airflow 90° to 180° several times as it passes through chambers or is deflected by baffles.

Q. How many diffuser discs should I run?
The answer depends on your displacement: disc diameter, power band, and noise level. Fewer discs reduce sound levels, more discs increase sound levels. Fewer discs increase low-end torque and richen the carbureted fuel mixture. More discs increase sound levels, increase top-end power and lean out the carbureted fuel mixture. NOTE: When tuning an exhaust system, start with fewer discs and add. Never start with a lot of discs and subtract. Generally on a stock set up (no engine modifications, and stock carb and air filter), you can start with six to eight discs on dirt bikes and ATVs. On V-twin, metric and cruiser bikes, start with twelve discs. A popular misconception: The more free-flowing an exhaust system is, the more power it will make. This is not true. Some backpressure (2-3 PSI) is necessary to achieve maximum power. This is why it is necessary to use the discs that come with your tunable SuperTrapp exhaust. The number of discs to use will depend on your application, displacement, disc diameter and power band. To assess the performance of any product that affects horsepower and torque, lap times and Dyno- runs are your best indicators. However, since most enthusiasts usually only have a “seat-of-the-pants” Dyno, running condition is the most obvious indicator. Pay attention to the coloration of the discs. Little or no disc coloration indicates a possible lean condition (remove one or two discs). Black or sooty discs are indicative of a rich, or oil burning condition (add one or two discs). Discs that turn a tan or golden color indicate an acceptable balance of fuel mixture and exhaust flow. Reading a spark plug is the quickest way to check if everything in the engine is working as it should. And, it will tell if the SuperTrapp has been tuned properly. A rust-brown spark plug color indicates that the plug is operating smoothly (exhaust is tuned correctly). A whitish look indicates that the burn is too lean (remove one or two discs). A blackish deposit on the plug electrodes (left by oil or fuel traces) indicates that the burn is too rich (add one or two discs).

Q. Will removal of the packing material increase performance?
In general terms, no. Example: A firmly packed SuperTrapp exhaust equipped with a 1-1/2-in. diameter core will maintain the same flow characteristics as the 1-1/2-in diameter exhaust tube that flows into it. However, if the material surrounding the perforations of the core tube is removed, or severely worn, this allows the exhaust to flow in and out of the perforations. This in-and-out movement introduces unwanted turbulence into the exhaust path. Consequently, this can harm the flow and performance.

Q. How often do I have to re-pack?
Re-packing should be considered when you notice that your exhaust is getting louder. SuperTrapp’s IDS Series and Kerker’s Performance Series are packed with a newer, better performing pillow pack sound absorbing material. If your exhaust is an older pipe, we suggest that you use pillow pack packing as it provides a slightly deeper sound and lower volume.

Q. How do I repack my IDS2?
To replace the packing, or remove the core, follow these six steps:

1. Take the muffler off of the bike.
2. Remove the end cap (three screws hold it on).
3. Remove the screw that is on the bottom of the backend of the muffler (holds the core in).
4. There are two rivets holding the nameplate. Drill out the rivet nearest to the back end of the muffler.
5. Put a dowel, or similar type of handle, into the inlet end of the muffler. At this point it will either hit a screen, or it will go all the way down to the discs. Tap against the discs, or the screen, and push the core out the back end of the muffler. If you have a Quiet Core you will have a screen. If you have a Race Core you can see straight through to the discs.
6. After removing the core, remove any left over packing. Next, make sure the holes in the perforated tube are clear. Wrap the new packing around the tube. Use masking tape at the top and around the middle to hold the packing in place. Then line up the holes and replace the core.

Q. Do I need to re-jet?
Re-jetting is suggested, but is not required. The best approach is to first put your new tunable SuperTrapp exhaust on your bike, or ATV, and tune it to the stock set-up. Once the SuperTrapp is tuned and running the way you want, you can then go up in the jet sizes, add a free flowing air filter, and add more discs for more horsepower.